This week's collaboration with What Is It? Blog brings us this strange transparent object: can you guess what it is for?

Place your guess in the comment section - one guess per comment, and please, post no URL (let others play now). You can enter as many guesses as you'd like. Prize this week: Free Neatorama T-Shirt (old design).

A Travelure, or as it's called on the the patent page: a "buoyant traveling device". From the patent:

...the device makes a steep dive in the water in the direction toward the fisherman when the fishing line is pulled or tugged, the device gliding upwardly and in the opposite direction away from the fisherman when the line is released, retreating to a greater distance beyond its initial position than the distance it was moved to cause it to dive.

It's patent number 3,401,483 , the diagram on the patent page shows it diving down one foot when the line is pulled and rising back to the surface three feet further from the fisherman, this would be useful for working the bait into difficult locations such as under a tree.

Its a Pligger-Towforth mechanical hearing aid. No batteries- No wires! You simply clench the indented end between your teeth and face the speaker. The sound is picked up by the parabolic receiver and transmitted to your 'inner ear' through your jawbone!

Pligger-Towforth went out of business after a young woman wearing the device accidently swallowed after emitting a gasp of surprise during a marriage proposal and died.

It is a type of fishing float. You can pull on the fishing line and cause it to dive underwater in a specific direction. It will then rise to the top. I used to fish with one of them and used it to 'cast' under a fishing dock.